What it is
Diazolidinyl Urea is a white powder.
What it does
Diazolidinyl Urea is a preservative that prevents bacterial growth. It works by releasing small amounts of formaldehyde.
Although Diazolidinyl releases toxic formaldehyde, the amounts are too small to pose a threat to human health. The Cosmetic Ingredient Review (CIR) Expert Panel considers Diazolidinyl Urea safe to be used in cosmetics up to a maximum concentration of 0.5%. In Europe, when the concentration of formaldehyde in the finished product exceeds 0.05%, the labels has to state “contains formaldehyde”.
However, Diazolidinyl Urea can cause irritations and allergies.